Rheostat



| KEBLER 1,779,601

RHEOSTAT Filed July 22, 1926 3 Sheets-Sheet 1 Oct. 28, 1930'.

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RHEOSTAT Filed July 22, 192 3 Sheets-Sheet 3 Patented Oct. 28, 1930 UNITED STATES PATENT ornca LEONARD KEBLER, F BRONXVILLE, NEW YORK, ASSIGNOR TO WARD LEONARD ELEC- TRIO COMPANY, A CORPORATION OF NEW YORK nnnosra'r Application filed; July 22,

This invention relates to rheostats having a series of contacts with adjustable means for controlling the resistance in the-circuit as desired. It more particularly relates to regulating rheostats adapted to be mounted upon a panel-board or other suitable support.

One of the objects of this invention is to provide a rheostat construction formed of totally enclosed units adapted to be built up and added one to the other to provide a total number of units for securing the degree and character of control desired; and to accomplish this by a simple construction which may be utilized and assembled by the manufacturer or the subsequent user. v

A further object is to provide a construction which is adapted to be mounted on the front or back of the panel-board without changing the construction so that the same device may be utilized for either character of mounting.

Further objects and advantages of the invention will be apparent from the following specification and accompanying drawings in which Fig. 1 is a front elevation of one embodiment of the invention illustrated as mounted on the front of a panel-board.

Fig. 2 is a side elevation of Fig. 1.

Fig. 3 is a sectional elevation on line 3-3 of FigI 2.

Fig. 4 is a sectional elevation on line H of Fig. 1. a

Fig. 5 is an elevation, partially in section, illustrating the invention as mounted on the back of a panel-board.

Fig. 6 is a sectional elevation on line 6-6 of Fig. 4-.

Fig. 7 is a perspective View of a means for connecting one lead to the rheostat arm.

Fig. 8 is a perspective View of a saddle for attaching the supporting members or legs to the unit, and

Fig. 9 is a perspective view of a terminal block for the lead connections.

* In the embodiment of the invention illusj. trated, the casing consistsof a sheet iron plate 1 having an outer rim or flange 2 turned at right anglesthereto to form a container-like structure forfthe resistance elements. The

1926. Serial No. 124,119.

inner surface of this iron plate contains an insulating material upon which is located the resistance elements connected toa series of circularly arranged contacts 3. The resistance elements are covered with a coating of vitreous enamel, but as this construction of the resistance elements and arrangement of the fixed contacts forms no part of the present invention, it need not be particularly referred to, and other suitable construction may be utilized.

The plate 1 has a central circular opening and the bearing member 4: welded adjacent thereto to form a relatively long center or main bearing for the hollow main shaft 5.

Attached adjacent to one end of the shaft at right angles thereto and rotated therewith,

is a drive arm 6. The arm 6 is provided with apertures diametrically opposite the shaft 5 for the two piece insulating spacers 7. The spacers 7 are constructed of insulating material and serve as a supporting means for insulating and attaching the contact member 8 to the metal arm 6. A split rivet- 9 passes through an aperture in the contact member 8 and the spacers 7 so as to secure the contact member to the drive arm 6, as clearly shown in Fig. 4.

The contact member is. provided with a central circular section 10 spaced from and concentric with the main shaft 5. This contact member is constructed of spring material and is bent over at one end 11 so as to contact with the circularly arranged contacts 3 upon rotation of the shaft 5. The end 11 is rounded back along its sides at 12 in order to provide a smooth contact as it glides over the contacts 3. The fixed connection 13 is attached at one end to the insulating terminal block 14 by means of a screw bolt 15, and makes at its opposite end a rotating contact with the contact member 6. Ring section 16 of the same diameter and width as the circular section 10 of the contact member 6, is provided at the end of the connector 13. This ring sect-ion 16 is provided with tabs 17 which are bent inwardly and around the circular sect-ion 10 with a spring phosphor bronze washer 18 therebetween in order to insure a perfect rotating contact at all times.

2 awasoi er rim or flange 2 of the plate lbyfneans of apertures 27 said bolts being held in place by nuts 28. These bolts also provide a means for securing stop 29 which has a sect1on 30 protruding in the path of the end of the drive arm 6. lhe drive arm contacts with th s stop on rotation, preventing further movement thereof.-

A metal terminal box orfittinga 31 surrounds the insulating terminal lock 14 straddling the units and having a cover 32 for the lead-in connectors. lhe terminal box orfitting with its cover is held in position by means of screw bolts 33 threaded into the heads 26 of the screw bolts'25 as shown inFig. 3. The cables containing the entrance leads for connectionto the rheostat units enter the terminal box through inlet 34 of the cover 33 and are then connected to the binding posts."

A back plate35 for enclosing the rheostat structure fits into the outer rim or flange 2 of the plate 1 and is held in place by means of saddles 36 spaced around the circumference of the flange 2, the plate 1 and the back cover providing an enclosing casing for each 35 unit.

lhe saddles 36 have side flanges 38, 39, 40 and 41. The flange 38 curves to fit the connection between the plate 1 and its flange 2, and the flange 39 .is bent at right angles to the-body portion to hold the back plate 35 in position. The flanges 40 and 41 are bent at right angles to the body portion providing a c annel for the supporting elements or legs 42. A central screw 43 is passed through apertures in 'the supportin elements 42, the saddles 36 and then threade to the flange 2-holding the supporting elements to the unit, and, at the same time, securing the saddles 36 for holding the back plate 35; thus forming a totally enclosed rheostat unit.

When two or more units operate together, a fitting 43 passing through an aperture in the back plate 35 is attached by means of a bolt 44 to the shaft 5 of the adjacent unit.

Secured to this fitting, within the unit, is an extension 45"having at its end two right angled extensions 46 which straddle the ex tension 47 struck out from the drive arm 6,

- making a connection therewith so thatrotation of the drive arm will be communicated to the adjacent unit or units as shown in Fig. 4. a

The shaft 5 is rotated by means of a handle 48. A fitting 49, with a washer 5Q1nterposed between it and plate 1, is attached to the bolts 25 which have heads 26 counter-sunk inshaft 5 by means of a s uare-headed screw bolt 51. The handle 48 ts over this fitting and is provided with a longitudinal slot for the square head of the screw bolt 51. To se-,.

cure thehandle to the shaft 5, a screw 52 is longitudinally threaded within the shaft 5 with its head in-an aperture 53 of thehandle. A cover plate54 serving if desired, as a name plate, is attached to the handle over the aperture 53, thus covering theattaching screw 52.

lhe supporting elements or legs 42 are provided at one end with attachin sections 55 which are bolted to the paneloard 56 by means of bolts 57 passing through the sections 55.

In Fig. 5 the rheostat units are shown as mounted on the back of the panel-board. n

The supporting elements .42 are reversed from the position shownin Figs. 2 and 4 and the unit attached to the back of theboard. Fitting 49 is attached to a shaft-extension 58 by means of a screw bolt 59. This shaft extension passes through the aperture in the panel-board and the handle 48 is attached thereto in the same manner as explained above.

A bushing 60 may be attached to the panelboard by means of screws 61 if it is desired to carry the handle out from the panel-board.

lit is apparent from the above description that the invention provides a construction for a rheostat unit and cooperating means which are adapted to be built up to any extent desired for front or back mounting. The units and their connections are each totallyclosed as described in the description.

While the invention has been illustrated and described more particularly with reference to one embodiment of the invention, it

is not confined thereto, but is intended to ooverany other uses or modifications within the scope of the appended claims.

I claim:

1. In a rheostat unit, the combination of resistance elements, a casing supporting and enclosing the resistance elements and having separable front and back portions, supporting elements for supporting said unit from a panel board, and devices interposed between the casing and the supporting elements,

said devices having extensions for engaging said front and back portions of said casing for holding them in assembled relation and having extensions for engaging said supporting elements for holding them perpendicular to the casing.

2. ln a rheostat unit, the combination of resistance elements, a plate supporting the resistance elements, a back plate for enclosing the resistance elements, supporting elements for supporting said unit from a panel board and devices inter osed between said plates and said supportln elements, said devices extensions or engaging said front bled relation and having extensions for also engaging said supporting elements for holding the said supporting elements parallel to each other and perpendicular to the plates.

3. In a rheostat unit the combination of resistance elements, a plate supporting'the resistance elements, said plate having an edge portion turned at right angles thereto, a back plate fitting within the edge portion of the.

front or back of a panel-board comprising saddle members and supporting elements, said saddle members having extensions for holding said plates in assembled relation and extensions for holding said supporting members perpendicular to said plates.

5-. In a rheostat unit, the combination of a plate having fixed contacts thereon, a shaft, a metal drive arm supported-by said shaft, a contact member, an insulating support carried by said drive arm for supporting said contact member and spacing same from said drive arm, said contact member contacting with said fixed contacts and having a circular portion surrounding and spaced from said shaft, and a fixed contacting member in continuous electrical connection with said circular portion.

6. In a rheostat unit, the combination of a plate having fixed contacts thereon, a shaft, a metal drive arm supported by said shaft, a contact member, an insulating support carried by said drive arm for supporting said contact member and spacing same from said drive arm, said contact member contacting with said fixed contacts and having a circular section surrounding said shaft, and a fixed contacting member having portions disposed circularly and having electrical connection with and embracing said circular section.

7. A rheostat unit comprising a plate having fixed contacts thereon, a drive arm,'a

member carried by and insulated from said drive arm having a circular section, a fixed connectorhaving a circular section with extensions for contacting with the circular section of said contact member and a contact washer interposed between sald contact memher and said extensions to provide extensive rotating contact surface between the contact member and the fixed connector.

8. A plurality of rheostat unitsspaced apart from each other and each comprising a complete unit having a separately enclosed supporting casing and a centrally operated shaft, a drive arm on each of said shafts, a handle on the shaft of the front unit, and a fitting on the shaft of an adjoining unit extending through the casing of the front unit, said fitting having an extension within the casing of the front unit engaging the drive arm of the front unit.

9. A rheostat comprising an enclosing case ing with a series of contacts, a rotating contact member, a terminal block for the terminals of said rheostat secured to said casing by means of screw bolts passing therethrough, a terminal box enclosing said terminal block and terminals extending from said casing, and screws passing through said terminal box and threaded into the heads of the screw bolts secured to said terminal block providing means for securing the terminal box to the casing.

10. A plurality of rheostat units each comprising an enclosing casing, a series of contacts and a rotating contact member within I each casing, a terminal block for the, terminals of each rheostat secured to each casing and a single terminal box for enclosing the entire series of terminal block s.

11. A plurality of rheostat units each comprising an enclosing casing, a series of contacts and a rotating contact member within each casing, a terminal block for the terminals of each rheostat secured by screw bolts to each casing, connections between the terminal blocks and a single terminal box for enclosing the terminal blocks and terminal connections of each unit secured to the casing by means of screws threaded into the heads of said screw bolts.

LEONARD KEBLER. 

